The adjustability of saws and other electric machine tools relative to a work surface, such as that of a workbench, has been a longstanding concern in the prior art. In applications such as the construction of roof trusses, in which numerous members having a variety of differently angled cuts must be generated in large numbers, factors such as the mobility, portability, ease of adjustability and repositioning of the tool, and weight of the system, are all important.
While numerical control machines have become commonplace in the control of many machine tools, for example, machine drills, lathes, files, and etching devices, a suitable numerical (or computer) control machine suitable for use with a power saw at a construction site, in which the cutting of many wood members having various angles is often required, has not appeared in any practical or economic form.
Efforts made along these lines that are known to the inventor include a programmable turntable manufactured by Speed Cut, Inc., of Corvallis, Oreg. 97339, and the so-called SPIDA Radial Saw, also manufactured by Speed Cut. Comparable products are offered by a handful of other companies around the world.
Systems such as those of Speed Cut, Inc. involve considerable weight, occupy a large volume and ground area, are heavy, costly, are not easy to adjust or program, and are time-consuming to maintain. Also, they are not as easy or convenient to work with in the field as might be desired.
At a more technical level, systems such as those of Speed Cut make use of articulated arms which extend directly from a rotatable junction with a workbench associated with the cutting system. The shortcoming of this structure is that vertical loads upon the arms are transmitted to a rotatable support joint. Therefore, a particularly robust structure is required with the relatively high costs attendant thereto. Also, achievement of proper registration between the cutting tool and the workpiece is complex where the workpiece is secured to a rotating joint with the workbench. That is, loads on vertical bearings are not evenly distributed, thus degrading accuracy of the saw blade. Understandably, systems of the above type also impart considerable wear on their moving parts. It is, therefore, as a response to the above set forth long felt need in the prior art that the invention is directed.